<!-- 方案二：动态渐变 + 玻璃拟态 -->
<!DOCTYPE html>
<html lang="zh">
<head>
    <meta charset="UTF-8">
    <title>登录 - 玻璃拟态版</title>
    <style>
        :root {
            --primary: #7f5af0;
            --secondary: #2cb67d;
        }

        * { margin: 0; padding: 0; box-sizing: border-box; }

        body {
            height: 100vh;
            background: linear-gradient(45deg, #16161a, #242629);
            display: flex;
            justify-content: center;
            align-items: center;
            position: relative;
            overflow: hidden;
        }

        .bg-blob {
            position: absolute;
            width: 500px;
            height: 500px;
            background: linear-gradient(45deg, var(--primary), var(--secondary));
            border-radius: 30% 70% 70% 30% / 30% 30% 70% 70%;
            animation: gradientMove 15s infinite;
            filter: blur(60px);
            opacity: 0.3;
        }

        @keyframes gradientMove {
            0% { transform: rotate(0deg) scale(1); }
            50% { transform: rotate(180deg) scale(1.2); }
            100% { transform: rotate(360deg) scale(1); }
        }

        .login-container {
            position: relative;
            width: 400px;
            background: rgba(255,255,255,0.05);
            padding: 40px;
            border-radius: 20px;
            backdrop-filter: blur(10px);
            border: 1px solid rgba(255,255,255,0.1);
            box-shadow: 0 25px 45px rgba(0,0,0,0.2);
        }

        .input-box {
            position: relative;
            margin: 30px 0;
        }

        input {
            width: 100%;
            padding: 15px 20px;
            background: rgba(255,255,255,0.1);
            border: 2px solid transparent;
            border-radius: 10px;
            color: white;
            font-size: 16px;
            transition: all 0.3s;
        }

        input:focus {
            outline: none;
            border-color: var(--primary);
            background: rgba(255,255,255,0.2);
        }

        .floating-label {
            position: absolute;
            left: 20px;
            top: 50%;
            transform: translateY(-50%);
            color: rgba(255,255,255,0.6);
            pointer-events: none;
            transition: all 0.3s;
        }

        input:focus ~ .floating-label,
        input:valid ~ .floating-label {
            top: -10px;
            left: 10px;
            font-size: 12px;
            color: var(--primary);
        }

        .login-btn {
            width: 100%;
            padding: 15px;
            background: linear-gradient(45deg, var(--primary), var(--secondary));
            border: none;
            border-radius: 10px;
            color: white;
            font-size: 16px;
            cursor: pointer;
            transition: all 0.3s;
            position: relative;
            overflow: hidden;
        }

        .login-btn::before {
            content: '';
            position: absolute;
            top: 0;
            left: -100%;
            width: 100%;
            height: 100%;
            background: linear-gradient(
                90deg,
                transparent,
                rgba(255,255,255,0.2),
                transparent
            );
            transition: 0.5s;
        }

        .login-btn:hover::before {
            left: 100%;
        }
    </style>
</head>
<body>
    <div class="bg-blob"></div>
    <div class="bg-blob" style="right: -200px; bottom: -200px;"></div>
    
    <div class="login-container">
        <h2 style="color: white; text-align: center; margin-bottom: 30px;">系统登录</h2>
        <div class="input-box">
            <input type="text" required>
            <span class="floating-label">用户名</span>
        </div>
        <div class="input-box">
            <input type="password" required>
            <span class="floating-label">密码</span>
        </div>
        <button class="login-btn">立即登录</button>
    </div>
</body>
</html>